Rolling sheets



L. JOHNSON ROLLING SHEET Filed Nov. 10, 1927 Jan. 5, 1932.

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R o T N E M Fatentedl den. 5, 1932 were stares PATENT OFFICE LANEJOHNSON, OF INGRAM, PENNSYLVANIA, ASSIGNOR TO UNITED ENGINEERING &FOUNDRY COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION 015 PENN-SYLVANIA ROLLING SHEETS Application filed November 10, 1927. Serial No.232,286.

1 This invention relates to the rolling of sheets or tin plate, andprovides a method and apparatus whereby the labor cost for a 7 givenproduction is materially lessened over that required for rolling sheetsfrom sheet bars, and whereby other operating costs are also materiallyreduced. v In carrying out my preferred method, I preferably first rollan ingot into slabs. This 10 operation can be readily carried out on aregular blooming millor slabbing mill. The slabs are preferably ofuniform cross section, regardless of the size and gage of the sheets tobe rolled. These slabs may be readily stored or may be passed directlyto the next stage in the operation;

.In the second stage, the slabs are passed through a hot strip mill andare reduced to strips which are preferably of uniform width, but whosethickness may vary in accordance with the gage or dimensions of thesheets desired.

The strips are sheared into lengths which are generally equivalent tothe width of the sheets desired, with, of course, due allowance forscrap. The sheared pieces are passed crosswise through a cold mill ormills so as to produce the break-down sheets. The break-down sheets maythen be doubled or paired and passed through a heating furnace, andsubjected to the usual hot rolling operations for the manufacture ofsheets or tin plate. This last operation, however, is materiallysimplified because the breakdown sheet is, say, only twice as thick asthe finished product.

Instead of a hot rolling operation to finish the break-down sheet, coldrolls may be employed to reduce it to final thickness. In

49 either case, the labor cost for the sequence of steps above recitedis materially lower than the cost of rolling by the old methods. The

handling may be practically all mechanical and the quality of the laboris changed. The

percentage of skilled labor required is also materially reduced.

The method is also of great advantage in that it is highly flexible.Sheets of various length, width and gage may be rolled with a minimum ofchanges in roll settings. The

material at various stages of operation; particularly the slabs, may bestored as desired, and chipping, pickling or annealing operations, orany other operations for imparting special qualities to the finishedsheet, may be interposed with but little difiiculty.

In the accompanying drawings which illustrate more or lessdiagrammatically the present preferred embodiment of my invention andcertain modifications thereof,

Figure 1 is a view showing a plant lay-out for carrying out my process,the final rolling being effected inhot mills,

Figure 2 is a similar view, but showing the sheets passed through theheating furnaces crosswise instead of lengthwise, and

Figure 3 is a view corresponding to a portion of Figure 1, but showingcold mills for reducing the break-down sheetby cold rollmg.

Referring first to Figure 1, there is shown a slabbing mill comprisinghorizontal rolls 2 and edging rolls 3. Slabs S of uniform cross sectionare produced on this mill. The

slabs are cut to length in a shear 4; which is interposed in the rolltable 5.

The roll table 5 extends to a hot strip mill, but a transfer mechanism 6is provided between the shear and the hot strip mill so that the shearedslabs may be carried to storage if desired.

The short slabs may be carried direct from the slab mill to the hotstrip mill and rolled with the original heat from the ingot, or they maybe reheated, or they may be chippedand reheated. Furnaces 7 are providedfor reheating the. slabs. These furnaces deliver the heated slabs to theroll table 5 so they may be carried to the hot strip mill. The hot stripmill, as herein illustrated, comprises a series of horizontal rollstands 8 and edging rolls 9. The stands are driven bymotors M in theusual way; I

The metal issues from the hot strip mill as strips 10. These strips areallowed to cool,

, lengths of 37 This gives a number of,

treated in any desired way, or the; may be pickled, sand blasted or shotblaste The short strips are delivered from the shear 11 onto a rolltable 13 by which the short strips are carried to a cold mill comprisinga plurality of stands 14. The piece 12 is passed crosswise through thestands 14 and issues as a breakdown sheet 15. It will be understood thatinstead of using a series of stands, as shown in Figure 1, a singlestand may be employed and the piece passed through several times. 7

The stands in the hot strip mill and in the cold mill may be of anytype, but it is preferred to employ four high stands in the cold mill,and in at least some of the passes of the hot strip mill.

The break-down strip 15 is carried by a roll table 16 to the vicinity ofthe heating furnaces 17.

After the matched or-doubled break-down sheets leave a furnace 17, theyare taken to sheet rolls 18 and are subjected to the usual processes forreducing them to sheets or tin plate. A finished sheet is indicated at Fin Figure 1. The sheet rolls 18 are driven in the usual way from a motorM and are provided with the customary drag 19.

In order to more clearly illustrate the process, we may take as anexample the rolling of'a twenty gage sheet, size 36 x 120". We may startwith an ingot 26 wide x 10" thick x 4 long. ThlS ingot will be reducedin the slabbing mill to a slab 3" thick x 24 wide and with a lengthcorresponding to the weight of the ingot. This slab is taken to theshear 4 and cut into shorter slabs, say, 5 long. If desired, the entireslab may be rolled into a strip without dividing it into shorter slabs,although for convenience of handling it will generally be referred toshear the long slab.

e 3" x 24" slab is rolled in the hot strip mill into a strip 23 wide x.210 thick. This strip is cut by the shear 11 into pieces 12, 23" wide,37 long and .210"

thick. The pieces 12 are then passed crosswise through the cold mill andreduced to break-down sheets 15, these sheets being 37 wide by 64 longby .075" thick, or

. about 14 gage.

The 14 gage break-down sheets are then matched in pairs and passedthrough the heating furnaces 17 and rolled in the mills 18 to sheets 37wide by about 128% long by .0375" thick, or 20 gage. The sheets arethentrimmed to the size wanted, that is to say, 36" x 120".

If it were desired to roll a sheet 36 x 120 by, say, 27 gage, it wouldonly be necessary to double the two sheets obtained by rolling accordingto the example just given, and finish" this pack on the sheet mill, thusproducing a pack of four sheets of 27 gage.

As another example, assume that it is desired to make sheets 42" x 120"by 24 gage. We will again make slabs of the same cross section, that isto say, 24" x 3", and these slabs may again be cut to 5 lengths. The

5' slabs will be passed through the hot stripmill so as to producestrips 23 wide x .140 thick, or 10 gage. These strips will be cut to 43lengths, and the pieces thus produced will be passed crosswise throughthe cold mill to produce break-down sheets 43 The break-down sheets willbe matched or doubled and passed through the sheet or tin plate mill toproduce sheets 43 wide x 128 long x .025 thick, or 24 gag These sheets,when trimmed to size in the shears, will give theproduct desired.

wide x 64 4" long x .050 thick, or 18 gage.

It will thus be seen that sheets of varying 7 rolls in a hot strip millare used for narrow strips, they can never be used for wider stripsunless the rolls are redressed- On the other hand, considerablevariation in the width of-the pieces fed to the cold mill may be hadwithout materially affecting their finish.

Figure 2 shows a modified mill lay-out which is similar in all respectsto the layout of Figure 1, except that the break-down sheets are passedcrosswise through the furnaces 17 a. A shear 20 for the finished sheetsis indicateddiagrammatically in this figure.

Figure 3 shows a part of a mill lay-out which differs from that ofFigure 1 in that the break-down sheet is reduced to final thickness bythe cold rolls. In Figure 3 the pieces 12a which come from the shears11a are passed through a cold mill comprising stands 1411. so as toproduce the break-down sheet 15a. The break-down sheet 12a is passedthrough a series of stands 21 in which it is cold rolled to produce thefinished sheet F. These breakdown sheets may be matched or doubledbefore the second cold rolling if desired.

The advantages of my invention arise from the fact that the hot stripproduced is always of uniform width, thereby materially reducing thenecessity for redressing rolls. The variations in width of pieces whichare cold rolled is relatively immaterial from this point of .view sincethe finish of the rolls is not so much affected as in the case of thehot mill. Other advantages arise from the simplicity of calculation ofthe sizes to be rolled at the various stages, and

because of the fact that a wide variety of sizes may be produced with aminimum of change in the setting of the rolls. If we consider thematerial at various stages of operation from the standpoint of storage,the number of different sizes required is relatively small,therebysimplifying intermediate operations and likewise simplifying theproblems of storage and of handling for intermediate operations.

In the appended claims the term sheets is used as a term of generaldefinition and not of limitation, and is intended to include sheetsemployed for the manufacture of tin plate, or other products.

While I-have illustrated and described the preferred form of myinvention, it will be understood that it may be otherwise embodied orpracticed within the scope of the following claims I claim 1. In themethod of rolling sheets, the steps consisting in hot rolling a strip,then passing the strip through cold rolls to produce a break-down sheet,and then subjecting the piece to further rolling to reduce it to finalthickness.

2. In the method of rolling sheets, the steps consisting in hot rollinga strip, then passing the strip through cold rolls to produce abreak-down sheet, and then subjecting the piece to further hot rollingto reduce it to final thickness.

3. In the method of rolling sheets, the steps consisting in hot rollinga strip, then passing the strip crosswise through cold rolls to producea break-down sheet and then subjecting the break-down sheet to furtherrolling to reduce it to final thickness.

4. In the method of rolling sheets, the steps consisting in hot rollinga strip, cutting it into pieces whose length is generally the width ofthe finished sheet, and passing the pieces crosswise between cold rolls.

5. In the method of rolling sheets, the steps consisting in hot rollinga strip, cutting it into pieces whose length is generally the width ofthe finished sheet, passm the pieces crosswise between cold rolls, anthen subj ecting the pieces to further rolling to reduce them to finalthickness.

6. In the method of rolling sheets, the steps consisting in hot rollinga strip, cutting it into pieces whose length is generally the width ofthe finished sheet, passmg the pieces crosswise between cold rolls, andthen subjecting the pieces to further hot rolling to reduce them tofinal thickness.

7. In the method of rolling sheets, the steps consisting in hot rollinga strip, then assing the strip crosswise through cold ro s, and thenmatching-or doubling the material and subjecting it to further rollingto reduce it to final thickness.

8. In the method of rolling sheets of vary- I ing sizes or gages, thesteps consisting in hot rolling strips of substantially uniform width,varying the thickness in accordance with the length and gage of thesheets desired, cutting length and gage of the sheets desired, cuttingsections from the strips, the sections being of a length which isgenerally the width of the finished sheets, passing the pieces crosswisebetween cold rolls, and then subjecting the pieces to further rolling toreduce them to final thickness.

10. In the method of rolling sheets of varying sizes or gages, the stepsconsisting in hot rolling strips of substantially uniform width, varyingthe thickness in accordance with the length and gage of the sheetsdesired, cutting sections from the strips, the sections being of alength which is generally the width of the finished sheets, passing thepieces crosswise between cold rolls, and then subjecting the pieces tofurther hot rolling to reduce them to final thickness.

11. In the method of rolling sheets of varying sizes or gauges, thesteps consisting in hot rolling strips of substantially uniform widthwhereby marking of the product by the rolls is obviated, varyin thethickness in accordance with the length and gauge of the sheets desired,cutting sections from the strips of a length equal to the width of thefinished sheets with trimming allowance, and passing the piecescrosswise between cold rolls so as to eliminate marking of the product.

In testimony whereof I have hereunto set In hand.

y LANE JOHNSON.

